Furnace



W. .LULOFS July 19, 1932.

FURNACE Filed Dec. 17, 1926 '2 Sheets-Sheet l iNVENTO R' WAR/YER LULOFSY j% PM ATTORNEYS July 19, 1932. w. LULOFS I 1,868,329

' FURNACE Filed Deg. 17, 1926 2 Sheets-Sheet 2 INVENTOR WflR/YER L ULoFs B Maw/f- J I ATTORNEYS Patented July 19; 1932 UNITED, STATES PATENTOFFICE. j

WARNER LULOFS, OF AMSTERDAM, v NETHERLANDS, ASSIGNOR TO THE BAIBCOCK &WILCOZ COMPANY, OF BAYONNE, NEW JERSEY, 'A. CORPORATION OF NEW JERSEYFURNACE Application flied December 17, 1926, Serial No.

My invention relates to improvements in a furnace for burning finelydivided fuel, such as pulverized coal or oil.

The invention will be best understood from the following description andthe annexed shows a modification in a section similar to that of Fig. 1.

Like reference characters indicate like parts throughout the drawings.

Certain embodiments of my invention are illustrated in the drawings inconnection with a portion only of a furnace of the fuel nozzle gype. Inthe form of my invention shown in igs. 1 and 2, a furnace chamber 10 isprovided with a roof 11 through which one or more fuel nozzles 12project to introduce the fuel into the chamber 10. The front wall 13 iscooled with the usual water tubes 14 connected to headers and to theboiler in the usual manner, the upper header 15 only being shown. Theroof 11 is similarly protected by and partly supported on boiler watertubes 16 with header connections of which the header 17 only is shown.

The front wall 13 is shielded by air heater ducts 19 contacting at theirsides ,with the wall tubes 14. These ducts have elbows 20 extendingthrough the wall 13 and communicating with a pressure box 21 receivingair from a suitable fan 22. Each duct 19 has at its upper end, agoose-neck 23 terminating in a nozzle 25 to discharge heated air fromducts 19 into the fuel entering from the nozzles 12.

These air ducts 19 preferably contact with the water tubes overapproximately the entire surface of the water tubes to insure a goodheat transfer from the air ducts to the water tubes. Fins 26 of anyshape or arrangement extend from the interior face of theexposed orheated wall of each of these air ducts to supply a better heat transferto the air within the ducts. The exterior faces of ducts 19 arepreferably flat and form a relatively continuous inner face to the wall.

At the bottom of each air duct 19 is a ledge or book 27 attached to theelbow portion 20 of 155,373, and in Great Britain March 12, 1926.

the duct. This ledge supports a cap 28 of refractory material to protectthe elbow and to impart a suitable finish to the top of the masonry wall29 on which the elbows20 of ducts 19 are supported. These ducts may beof metal, such as cast iron, or of refractory material, as desired. Thespace 30 between the ducts l9 and the exterior of the wall may, ifdesired, be filled in by any suitable masonry construction. 1

The modification of Fig. 3 permits the heating of the combustion airwithout exposing the metal heater ducts to the hottest portion of theflame or for such an extent or over so great a portion of the wall areain the furnace chamber as in the formshown in Fig. 1. These air heaterducts 31 have elbows 32 extending through the outside wall of thefurnace to the pressure box 21, andresting on the masonry wall 29. Theducts are placed between and in contact with the water tubes 14 as arethe air ducts 19 of Fig. 1, but are shorter than the ducts 19 and.extend through only a limited vertical distance.

The water tubes are embedded above the ducts 31 in the center of arefractory wall 33, carried. on the upper elbow sections 34 of the airducts 31. This wall is spaced from the outer wall 13 of the furnace,thereby forming an air space 35, wherein air rises from nozzles 37 ofthe air ducts. This air is discharged into the fuel through suitablyarranged outlets38. in the top of wall 33. In all other respects thefurnace disclosed in Fig. 3 is similar to that of Fig. 1.

Since the air is heated by radiant heat, the quantity of heat suppliedto the combustion air is substantially constant, so that, at low ratesof combustion, the smaller quantity of air used can be heated to hightemperature, an advantage at light loads.

It is obvious that various changes may .be made within the limits ofthis invention without departing from the scope thereof and within thelimits of the appended claims.

I claim:

1. In a furnace, metallic air heater ducts forming a substantia iycontinuous wall surface exposed to the radiant heat in the furnace, saidducts having inlets to admit air to the bottom of the ducts and outletsto sup-- ply air from the upper portions of the ducts to the furnacechamber, and water tubes between said ducts and separate therefrom.

2. In a furnace, air heater ducts forming a substantially continuousmetallic wall surface exposed to the radiant heat in the furnace, saidducts having inlets at their lower portions to admit air to: the ducts,a fuel burner at the upper part of the furnace, said ducts havingoutlets at their upper ends to supply heated air to the incoming fuel,and water tubes between said ducts and separate therefrom.

3. In a furnace, metallic air heater ducts forming a substantiallycontinuous wall surface exposed to the radiant heat in the furnace, saidducts having inlets to admit air to the ducts and outlets to supply airfrom the ducts to the furnace chamber, and water tubes separable fromsaid ducts contacting a portion of the wall of each of said ducts andextending'beyond the ends thereof.

4. In a furnace, metallic air heater ducts forming a substantiallycontinuous wall surface exposed to the radiant heat in the furnace, saidducts having inlets to admit air to the ducts and outlets to supply airfrom the ducts to the furnace chamber, and water tubes contacting aportion of the wall of each of said ducts, each duct having a depressionin the wall thereof enclosing approximately one-half of thecircumferential area of one of said water tubes.

5. In a furnace, metallic air heater ducts forming a substantiallycontinuous wall surface exposed to the radiant heat in the furnace, saidducts having inlets to admit air to the ducts and outlets to sup 1y airfrom the ducts to the furnace chamber, and water tubes contacting aportion of the wall of each of said ducts, each duct having a depressionin the wall thereof enclosing approximately one-half of thecircumferential area of one of said water tubes, said ducts beingsupported so as to be free to expand longitudinally when heated.

6. In a furnace, a wall having an outer and an inner portion spacedapart, metallic air heater ducts forming a substantially continuous wallsurface exposed to the radiant heat in the furnace, said air ductsforming at least a part of the inner wall, said ducts 8. In a furnace, avertically-extending metallic' air duct forming part of the wall of thefurnace, the lower portion of the duct having an elbow extending outthrough the furnace wall, a refractory wall on which said elbow rests tosupport the duct, said elbow having a projection adjacent the innersurface of the wall, and a refractory tile attached to said projectionto protect the elbow tubes.

- WARNER LULOFS.

having inlets to admit air to the ducts and outlets communicating withthe space between the inner and the outer walls, said inner wall. havingopenings connecting said space with the furnace chamber.

7. In a furnace, a furnace wall, a vertically extendin metallic air ductforming part of 'a wall 0 the furnace,,the lower portion of the ducthaving an elbow extending out through the furnace wall, and a refractorywall on which eibo'w ranets to support the duct.

